Skeletal System

Fact

The study of bone: "Osteology"

This system in adulthood has 206 bones but at birth 270

The skeleton can be broken into 2 categories:

Function

Bone is living tissue that provides several key functions. Some are involved in the structure of the human body and some play a role in the function of vital process of life.

Support: rigid framework for soft tissues and organs

Protection:

Body movement:

Anchoring attachments for most skeletal muscles

Hemopoiesis:

Mineral storage:

Types

Long Bones:

Short Bones:

Flat Bones:

  • Broad dense surfaces for muscle attachments
  • For protection of underlying organs (cranium, ribs, shoulder girdle)

    • Irregular Bones:

    Sesamoid Bones

    Growth and Maturation

    Bone is a living tissue. It is constantly growing, recycling, and maturing through our lives. There are 3 specific bone cells, each having their own role in the growth and maturation of our skeletal system.

    Osteocytes:

    mature bone cells

    Osteoblasts:

    bone-building cells

    Osteoclasts:

    bone-destroying cells (growth, healing)

    Need To Know Examples

    These are the bones you are responsible for:

    Muscular System

    Muscular System - Fact

    There are approximately 650 skeletal muscles in the human body.

    A muscle can only “act” when it receives signals from the nervous system.

    The release of the signal to control a muscle can be both voluntary (controlled) or involuntary (not controlled) from the nervous system.

    Each muscle attaches to bone at both ends. One end called the origin which is often the proximal location, and the other attachment is the insertion, which is commonly the distal end of the muscle.

    In a muscle contraction, the insertion always moves towards the origin.

    Muscles make up 40% of your total body weight.

    Muscles cannot push, they must always pull.

    Muscular System - Function

    The function of muscle is to attach to bone and when activated contract, thus bringing the bones attached at each end of the muscle together. This is known as a muscular contraction.

    There are three types of muscle contraction, as shown in the diagram (top to bottom):

    Muscular System - Types

    There are 3 types of Muscle Tissue:

    Smooth Muscle

    Cardiac Muscle

    Skeletal Muscle

    Muscular System - Growth and Maturation

    Muscle can either grow or shrink depending on the load that is placed on the muscle.

    Muscle hypertrophy involves an increase in size of skeletal muscle through a growth in size of its cells as a result in an increased demand or load placed on the muscle.

    Muscle atrophy is defined as a decrease in the mass of the muscle which can be a partial or complete wasting away of muscle, This is most commonly experienced when persons suffer some type of loss of demand on the muscle such as an injury, disease or even a lock of gravity (space).

    Reasons for Growth:

    Muscular System - Growth and Maturation

    You are responsible for researching what movement each muscle performs for each of the following muscles.

    Articular System

    Articular System - Fact

    The articular system deals with joints of the body and the surrounding tissues.

    Components of articular system:

    Ligaments: band of fibrous tissue that connects 2 bones and provides the attachment for the cartilage, fascia and muscle.

    Tendons: connects the muscle to the bone

    Cartilage: fibrous tissue that covers the ends of bones, can withstand great amounts of pressure and tension and provides a cushion for the joint

    Joints are points of contact between 2 or more bones.

    Joints can be classified into 3 types:

    Fibrous Joints:

    Cartilagenous Joints:

    Synovial Joints: All synovial joints contain these 7 common components:

    Articular System - Function

    The function of the articular system is:

    1. To allow motion of the musculoskeletal system.
    2. To bear weight.
    3. To hold the skeleton together.

    Articular System - Types

    When we think of joints in the human body, we think specifically of synovial joints. There are 6 different types and each one has a specific movement that makes them ideal for their location.

    Gliding joints

    Hinge joints

    Pivot Joints

    Condyloid or Ellipsoidal Joints

    Saddle Joints

    Ball-and-Socket Joints

    Advantage/Disadvantages:

    Articular System - Growth and Maturation

    The older we get the cartilage around the end of our bones and joints, naturally deteriorates. The smooth tissue that cushions joints and helps them move more easily disappears with age. Basically, wearing out the body’s natural shock absorbers.

    In addition, we lose muscle tone and bone strength the older we get thus putting more stress on areas of articulation (joints).

    Articular System - Need to Know Examples

    These are the joints in the body that you need to know and what type of joint they are.